EP3109311B1 - Solar gas installation which can be operated in multiple modes - Google Patents

Description

The invention relates to a method for the separation of organic material from the aerobic section of a combined fermenter and its implementation in biomethane in the anaerobic section and an apparatus for carrying out the method.

The production of biogas from plants is a promising technology for achieving the energy transition. Due to its simple storage capacity and its high energy content, biogas is one of the most effective energy sources. Since 2012, however, legal and spatial restrictions have almost stagnated the construction of new biogas plants in such pioneering countries as Germany (Fachverband Biogas Prognosis, June 2014), according to which the number of installed plants will rise by only 61 to 8005 in 2015). The problem is in addition to high arable land use, which increasingly increases the cost of growing food, the costly growth and harvest of plants and the purification of biogas, the energy-consuming central supply of the population with the energy source. Compared to terrestrial plants, phototrophic microorganisms (PTM), which include i.a. Cyanobacteria, seagrass and tang include higher growth rates and higher productivity (Dismukes et al., 2008 FHI report). The cultivation of PTM is not in conflict with the production of food, as PTM cultivation is not tied to the use of arable land. Rather, PTMs are extremely modest and can be cultivated in places that are not usable in agriculture and industry, such as on sealed areas, coastal areas, on non-productive soils such as e.g. in the desert or at salt water sources that do not have the appropriate water quality. In the broadest sense, PTMs only require carbon dioxide, sun and trace elements to live and grow. The resulting independence not least enables a decentralized supply of the population with profitable energy.

PTMs, with an estimated more than 45,000 species, represent a biotechnological and economic potential that is far from exhausted. Because they use carbon dioxide as an alternative to plants to build organic material that is released during combustion, an energetic recycling of carbon dioxide is possible without contributing to further global warming. The pure fermentation of PTM to biogas is not very effective because the resulting biogas is contaminated with ammonia and hydrogen sulfide and the purification of the biogas and the pretreatment of the PTM costs a lot of energy. In contrast, it has been recognized that non-growing PTMs, which are comparable to microscopic factories to build organic or inorganic material, are more suitable for the production of pure biogas. You do not need fertilizer and energy consumption is low after growth in the production phase. Biogas is not produced by PTM itself. However, they can produce intermediates that are further metabolized to biogas by a partner organism, both of which are more effective overall than producing PTM alone.

From the DE102007031688A1 For example, a method is known in which algae produce hydrogen and oxygen from carbon dioxide and water, which in a further step is converted into methane by methanogenic bacteria. CN103571876A has improved this method by regulating the disruptive oxygen release of algae. Both methods have the disadvantage that only energy consuming strength is built, from which hydrogen and oxygen is produced in the course. It has been found that photovoltaic energy production is more efficient than photosynthetic energy production relative to the synthesis of glucose (Blankenship RE et al., 2011). In natural light, the efficiency is actually only 1 to 2% (Barber J. 2009). Added to this is the loss of energy in the conversion to hydrogen, which leads to an efficiency of 0.005% in the comparable cyanobacteria. Only by genetic modification was an efficiency of about 1% achieved (Masukawa H. et al., 2012).

DE102010040440A1 relates to a bioreactor in which photosynthetically active microorganisms are supplied with carbon dioxide and oxygen and excrete glycolate, which is separated by a membrane and used under anaerobic conditions as a substrate for methanogenic microorganisms, which convert it into carbon dioxide and methane. The method has the disadvantage that there is no exclusively for glycolate-selective membrane and that a stripping chamber is not sufficient to reduce the oxygen content sufficiently. Furthermore, it is unclear how the atmospheric carbon dioxide enters the system. For the use of a gas mixing device not least separate gas storage with the respective high purity gas are necessary, the filling affects at least the energy balance. Other unresolved problems are the supply of microorganisms with nutrient gas or oxygen and the nutrient supply in continuous operation in two different media. Last but not least, it does not take into account that unadapted methanogenic bacteria are attacked by organic acids. Subject of the device according to the invention DE102009008601A1 is a three-chamber device in which gas is exchanged between the first and second chambers via a gas-permeable and liquid-impermeable membrane for the treatment of a biological fluid and a fluid exchange between the first and third chambers through a membrane.

The invention is intended to solve the problem that high partial pressures of oxygen prevail in the production of organic material in a partial region of a fermenter, wherein in a further partial region, which is in communication with the first, these high oxygen partial pressures are to be avoided. Furthermore, the problem should be solved that carbon from the air in energy sources in a fermentation process should be integrated without much energy.

According to the invention the object is achieved by the method described in claim 1, wherein the device described in claim 11 is suitable for carrying out the method.

The invention is based on the scientific basis presented below.

PTM produce and secrete organic material at certain physiological conditions, i. Carbon compounds such as organic carboxylic acids. In glycogen synthesis, Synechocystis sp. For example, PCC 6803 produces ∟-ketoglutaric acid and pyruvic acid in the absence of nitrogen (Carrieri D. et al., 2015).

When compared to air-enhanced oxygen-to-carbon dioxide ratios, PTMs produce organic material of particular biotechnological interest during the calibra- tion cycle, during which carbon dioxide is fixed under normal conditions and used to build up glucose for energy. This phenomenon is based on the fact that ribulose-1,5-bisphosphate carboxylase / oxygenase (RuBisCO) also accepts oxygen as an alternative to carbon dioxide, with the KM value for oxygen being 350 μmol / l higher than for carbon dioxide having 9 μmol / l is. Long ago, in the Earth's atmosphere, the oxygen content was so low that this process did not matter. Reaction with oxygen produces 3-phosphoglyceric acid (3-PGA) as well as 2-phosphoglycolic acid (2-PG), which can no longer be used in the Calvin cycle or otherwise in the organism and therefore has to be recycled or secreted by other biochemical reactions , The metabolic pathway used to regenerate carbon for the calvary cycle is considered one of the most wasteful processes on earth. On the other hand, this circumstance can be used for the natural biotechnology on which the process according to the invention is based.

-Ketoglutarsäure mit Stickstoff-Donoren oder Glutaminsäure entstehen (Bauwe H. 2011). Im Unterschied zu Cyanobakterien finden die Stoffwechselwege in eukaryotischen PTM in verschiedenen Kompartimenten statt. Zum größten Teil wird aus 2-PG 3-PGA regeneriert und wieder in den Calvinzyklus geschleust, wobei Kohlenstoffdioxid frei bzw. "ausgeatmet" wird. Um weiterhin Glycolsäure zu produzieren, ist ein Auffüllen des Ribulose-1,5-bisphosphat-Pools notwendig, was nur durch zwischenzeitliche Kohlenstoffdioxidaufnahme geschehen kann.Dealing with 2-PG, the first stable intermediate after the calvary cycle, varies from organism to organism. 2-PG is converted into glycolic acid (hydroxyacetic acid) by dephosphorylation, partly secreted ( FIG. 11 ) partly to glyoxylic acid metabolized ( FIG. 10 ). This is in turn also partially secreted or further metabolized, with some hydrogen peroxide, glycine, L-serine,

-Ketoglutaric acid with nitrogen donors or glutamic arise (Bauwe H. 2011). In contrast to cyanobacteria, the metabolic pathways in eukaryotic PTM take place in different compartments. For the most part, 2-PG 3-PGA is regenerated and returned to the calving cycle, releasing or "exhaling" carbon dioxide. In order to continue to produce glycolic acid, a filling of the ribulose-1,5-bisphosphate-pool is necessary, which can only be done by interim carbon dioxide uptake.

Archaea, who produce biomethane, known as methanogens, use organic material and use it to produce biomethane. A distinction is made between acetate-splitting (acetotrophic) and hydrogen-oxidizing (hydrogenotrophic) methanogens. The acetotrophic methanogens split off methyl groups from organic material and reduce them to biomethane. For this they use the coenzyme methanophenazine. Among them are Methanosarcina. It was already shown in 1973 that anoxic microorganisms can only grow with glycolic acid as sole carbon source (Kurz WGW et al 1973, Edenborn HM et al., 1985). Friedrich M. et al. 1991 and Friedrich M. et al. In 1996 two acetotrophic strains were discovered that grow on glycolic acid and produce methane in a mixed culture, where: 4 C2H4O3 (glycolic acid) -> 3 CH4 + 5 Co2 + 2 H2O. Egli C. et al. In 1989, methanogens were able to live with monochloroacetate and dichloroacetate as the source of carbon and energy.

Hydrogenotrophic methanogens such as Methanococcus, Methanobacterium and Methanopyrus, on the other hand, form methane by reducing carbon dioxide with hydrogen to form methane and water or by converting formic acid. They do not have the enzyme methanophenazine. Most of the methanogens require an anoxic, pH neutral or weakly basic medium with at least 50% water. Water deposits, overgrown soils such as bogs and rice fields, manure, manure and the gut of ruminants are excellent biotopes for methane producers. Inhibitors of methane formers are organic acids, disinfectants and oxygen.

The reaction equation for the formation of biomethane in the course of the overall process according to the invention is: CO2 + 2H2O -> CH4 + 2O2.

In order to accustom microorganisms to particular media components, food sources and metabolic end products of other microorganisms, the microorganisms are gradually adapted to the components. This occurs in a turbidostat, which, when growth or population density decreases, reduces the inflow of medium with the component to be acclimated and increases the inflow of medium more suitable for growth. This system not only exploits the fact that some microorganisms have evolutionary pathways through metabolic pathways that are not needed in their respective preferred habitats. Stable strains are also produced by mutations in long-term projects. By this method, it is possible to adapt methane formers to organic material, in particular organic acids, as the only source of carbon or energy without genetic manipulation.

The process of the invention is more efficient than the production of glucose-based biofuels, in which the efficiency of glucose synthesis is only 1-2% (Linder H. 1998). Approximately 36% of the irradiated solar energy is stored by the light reaction of photosynthesis in ATP, since four Einstein red light with each 172 kJ correspond to 688 kJ and for the transport of 2 moles of electrons or 218.9 kJ, whereby 1 mol of ATP with 30, 6 kJ is formed (together 249.5 kJ), which is used for the carbon fixation in the Calvinzyklus. Together with the consumption of NADPH, the efficiency of the calvary cycle with structure and secretion is about 25% (Nabors M.W. et al., 2007). Methane formation by the archaea is very efficient at around 70% (Bernacchi S. et al., 2014). The overall efficiency of the formation of biomethane according to the invention is the result at about 18% of the irradiated solar energy. Thus, the efficiency is higher than in photovoltaics, which only reaches 16% there.

The solution according to the invention is described below. The method according to the invention is based on a sequence of modes which, starting with the production mode, are shown below.

In the method according to the invention PTM produce in a first section in the production mode organic material in particular glycolic acid under oxic conditions of carbon dioxide and oxygen and secrete it into a medium. They use sunlight and the trace elements present in the medium. Your growth is set. You do not need fertilizer to grow or other growth necessary Ingredients in the medium. The organic material is secreted by natural means. It arises in the cells through the use of oxygen instead of carbon dioxide (right side in FIG. 8 ).

After the production of the organic material, which advantageously requires a light irradiation of 100 to 200 μE / m ² · s of more than one hour, in the exchange mode, the medium containing the organic material is fed to a second section in which the organic Material is reacted by methanogens under anoxic conditions in biomethane. During the transition to the second section, the medium is degassed by oxygen so that the harmful for the methanogenous oxygen does not enter the second section. Up to a residual oxygen content of 4%, the methanogens are not endangered. For example, based on glycolic acid, on average 0.24 ml of biomethane per mg of glycolic acid is converted (Günther A. et al., 2012). In a total fermentor cycle, ie in a cycle involving both sections of the combined fermenter, the medium is again gassed with oxygen on the return to the first section to recover the oxic conditions for the production of the organic material in the first section. The medium in which the PTM is exemplified here by cyanobacteria such as Gloeothece 6909 and the methanogens such as clostridia such as Synthrophobotulus glycolicus or FIGlyM (Friedrich et al., 1996) and Methanococcus maripuladis preferably has at least the following composition: Media component Quantity in g / l KH ₂ PO ₄ 0.12 K ₂ HPO ₄ 0.12 NaNO ₃ 0.15 KCl 0.42 NH ₄ Cl 0.25 CaCl ₂ × 2 H ₂ O 0.12 resazurin 0.75 x 11 ^-3 Na ₂ S x 9 H ₂ O 0.40 NaHCO ₃ 3.75 L-Cysteine HCl x H ₂ O 0.40 EDTA 0.005 NaCl 4.50 MgCl ₂ × 6 H ₂ O 1 Trace element solution SL-10 (according to Wolfe) 1 ml Vitamin solution (according to DSMZ medium 141) 10 ml

The medium results from the components recommended by the DSMZ, Leibniz Institute - German Collection of Microorganisms and Cell Cultures GmbH and Bold's Basal Medium suitable for cyanobacteria (Stein J. 1973).

In a preferred embodiment of the method according to the invention, while the contact to the second section is interrupted, the medium is degassed from oxygen and fumigated with a return air from the environment, then the air from the PTM used for carbon assimilation (regeneration mode) and then the medium Degassed from air and gassed in a return with oxygen. After the consumption of the organic material in the second section and the consumption of carbon compounds, which serve as starting material for the production of the organic material in the PTM and are present in particular in the reductive Pentosephosphatweg, advantageously according to the twice to four times the time of light irradiation in the production mode, it is advantageous to initiate the regeneration mode. It serves to replenish the C3 pool in the Calvin cycle (Lorimer GH et al., 1981) and the PTM's own carbon supply ( FIG. 8 ). In production mode, with a higher oxygen content, 2-PG and 3-PGA ( FIG. 9 ), which enters the calving cycle again. However, the calvene cycle is lost net in every reaction of RuBisCO carbon. In order to compensate for this loss, it is necessary in the meantime to reduce the oxygen content in favor of carbon dioxide. The best way to do this is to use the atmospheric air, which is expected to consume its warming carbon dioxide. In the presence of the carbon dioxide, this is converted exclusively into 3-PGA. Part of it is used for the regeneration of the C3 pool and the other part for building up body-own carbon compounds such as glucose to supply the organism ( FIG. 8 ). In regeneration mode, contact with the second section is interrupted. The PTMs are illuminated because the enzymes of the calvary cycle are only active when illuminated.

In the transition from the production mode with a high relative oxygen content in the medium to the regeneration mode with dissolved air in the medium, the medium is preferably derived from the first section and degassed by oxygen. Subsequently, the medium is preferably gassed with air and fed back to the first section, whereby a partial reactor circulation is established. The exchange with the second section is preferably interrupted.

The transition from the regeneration mode to the production mode is preferably carried out in the partial reactor circuit with interrupted contact with the second section by degassing the medium of air and gassing with oxygen.

In a preferred embodiment of the method according to the invention, the ratio of carbon dioxide to oxygen in the medium in the first section in the production mode is low, preferably 1: 800 to 1: 3000. This corresponds to the range in which RuBisCO increasingly accepts oxygen and the organic material precursors are produced by the PTM without the oxygen content being toxic. In contrast, the ratio in the regeneration mode according to the air composition is 1: 500. The reduction of the carbon dioxide-oxygen ratio is achieved by degassing the air and gassing with oxygen in the transition to the production mode.

In a preferred embodiment of the method according to the invention in the exchange mode, the medium is gassed during the transition from the first section to the second section after the oxygen degassing with a replacement gas from a replacement gas storage in particular with carbon dioxide or nitrogen. As a result, the methanogens do not come into contact with oxygen, but with a harmless gas for them. The carbon dioxide can be recovered in particular from the biogas and initially supplied to the replacement gas storage. Nitrogen is also suitable as a replacement gas due to its inert character and is also ubiquitous in the air. When returning before the oxygen fumigation, the medium is degassed from the replacement gas again. The medium is in the degassed state receptive and in need of oxygen. Thus, again high Oxygen partial pressures can be achieved in the first section. The recovered gas is stored again in the replacement gas storage, so that it is not lost and can be reused for fumigation.

In a preferred embodiment of the method according to the invention, the carbon dioxide is separated from the biogas produced in the second section by a biogas filter and stored in the replacement gas storage for the replacement gasification described. In addition, with excessive carbon dioxide accumulation in the replacement gas storage, the carbon dioxide can be used in the regeneration mode instead of the air. The separation of biogas in biomethane and carbon dioxide is preferably carried out by a Hohlfaserkontaktor. In this case, carbon dioxide is separated from the gaseous fiber through the pores of the hollow fibers, which are smaller than 0.05 microns, while the slower passing through biomethane remains in the hollow fiber and is forwarded. It can then be stored in a bioethanol storage and used to generate energy without further ado. It is particularly advantageous that the concentrations of toxic nitrogen compounds such as nitrogen oxides and ammonia and sulfur compounds such as hydrogen sulfide are negligible, preferably less than 0.1%.

In a preferred embodiment of the method according to the invention for filtering and degassing filter in particular hollow fiber contactors are used, wherein the pore size is less than 0.1 microns, preferably below 0.04 microns. The preferably to be used hollow fiber contactors are characterized by a high efficiency and low energy consumption in the degassing of liquids. During degassing, the medium is passed through the hydrophobic hollow fibers, which are present in large numbers in the contactor at the beginning and at the end (FIG. FIG. 7 ). Due to the high number of fibers, a very large surface is achieved. Due to the small pore size and the hydrophobicity, only the gas molecules pass through the membrane, which is amplified by a negative pressure. In the fumigation, it is the other way round, ie by an overpressure, the gas molecules are pressed into the liquid, without liquid molecules can get to the other side. For carbon dioxide and oxygen, due to their different properties, preferably different contactors with the following properties of the hollow fibers are used: Membrane contactor for carbon dioxide oxygen Outer diameter (in μm) 300 300 Inside diameter (in μm) 200 220 Bubble point (in psi) 240 240 Porosity (in%) 25 40 Pore size (in μm) 0.03 0.04

The preferred hollow fiber contactors for degassing and gassing have an inlet and outlet for the liquid flow. In each case an input space and an output space are connected. In between are the hollow fibers, which are fixed on both sides by a partition wall. The partitions limit the permeate space through which the hollow fibers are stretched. An opening of the permeate space is followed by a pump. When degassing, it is a gas pump that removes the gas from the Hollow fibers leads away, thus from their point of view, a vacuum pump. In FIG. 7 for fumigation, it is a gas pump that conducts the gas to the hollow fibers and creates an overpressure in the permeate space. The use of hollow fiber contactors has the particular advantage that an optimal supply of microorganisms with gas, as with their help, the gas can be best solved in the medium, whereby a better and more energy-saving supply than by conventional methods such as spraying and mixing is achieved. We have found that by using hollow fibers in particular the oxygen content can be reduced below 3%.

In a preferred embodiment of the method according to the invention come in the first section as PTM cyanobacteria in particular Gloeothece 6909, Plectonema boryanum, Anabaena sp. and Nostoc sp. in front. It turns out that cyanobacteria are very suitable for the process according to the invention. In contrast to green algae, which do not absorb in the so-called green space, they can absorb the light of all wavelengths with the help of phycobillins and convert it into chemical energy (MacColl R. 1998). The efficiency of light utilization is even higher with phycobillin phycoerythrin than with chlorophyll. As a result, cyanobacteria can successfully colonize even low-light areas, such as those found on the underside of river boulders or deep layers of lakes (Sari S. 2010). Consequently, in production mode, they can produce organic material even at low light intensities. Furthermore, cyanobacteria are preferred because they are light and temperature robust, i. withstand higher irradiation and lower temperatures without major damage (Latifi A. et al., 2009). They belong to the oldest living beings and have settled nearly every habitat of the earth. In contrast to eukaryotic PTMs, they have no comparable cell compartments, so they are relatively easy to analyze and manipulate. Not least, they are for the inventive method due to their high production rates of organic material advantage. The types and genera mentioned are distinguished, for example, by high production and secretion rates of glycolic acid (Renström E. et al., 1989). Further preferred are biofilm-forming cyanobacteria. The species and genera mentioned form in the first section said biofilm and are thereby not transported to the second section. Further preferred are slightly the produced organic material metabolizing cyanobacteria. A strategy of the cyanobacteria to deal with produced organic material, the secretion into the surrounding environment instead of the energy-intensive conversion in usable for them intermediates. Preference is given to species that metabolize not more than 10% of the organic material. Many green algae such as Chlamydomomas reinhardtii produce glycolic acid to a considerable extent. However, they metabolize them to a great extent (Moroney J.V., et al., 1986), which makes them less suitable for the process of the invention. As a result of the method according to the invention, it is possible to use a technology which is free of genetic engineering and can also be used by the consumer.

In a preferred embodiment of the process according to the invention, the methanogens in the second section are a mixture of acetotrophic and hydrogenotrophic Archaea. The acetotrophic archaea, in particular Methanosarcina sp. or Synthrobobotulus sp. split the organic material from the first section into carbon dioxide and hydrogen. It is then used by hydrogenotrophic archaea in particular Methanocella paludicola, Methanocella arvoryzae or Methanopyrus kandleri for biomethane production. Also preferred in the second section are mixed cultures obtained by selection from lake and marine sediments, from bovine rumen, from the intestine of termites and other animals, paddy fields, swamps or biogas plants. In the selection of the Archaea is added to the exclusive carbon supply by means of organic material that stepwise preferably in the above-described turbidostatic. For this purpose sewage sludge from a conventional biogas plant was used by the inventors.

In a preferred embodiment of the method according to the invention inhibitors of the intracellular degradation of the organic material and the intracellular carbon dioxide storage are present in the first section. Inhibitors of intracellular degradation of glycolic acid are, for example, 3-decyl-2,5-dioxo-4-hydroxy-3-pyrroline (Stenberg K. 1997), 4-carboxy-5- (1-pentyl) hexylsulfanyl-1,2, 3-triazole (Stenberg K. 1997), butyl 2-hydroxy-3-butynoate (Doravari S. et al., 1980) and α-hydroxy-2-pyridinemethanesulfonic acid (Zelitch I. 1966), which mainly inhibit glycolic acid oxidase. Inhibitors of carbon dioxide storage include acetazolamide (Moroney J.V. et al., 2001) and glycolaldehyde (Miller A.G., et al., 1989), which suppress the conversion of carbon dioxide to bicarbonate, a storage form of carbon dioxide. The inhibitors are preferably added to the medium in the first section to optimize the production of organic material.

In a preferred embodiment of the method according to the invention, the expression and / or the activity of glycolic acid dehydrogenase (EC 1.1.99.14) and / or glycolic acid oxidase (EC 1.1.3.15) is suppressed in the PTM or appropriate PTMs are selected on the basis of activity measurements. The suppression occurs, for example, by shRNA (small hairpin RNA), an RNA molecule with a hairpin structure that can artificially shut down genes by RNA interference (RNAi). Alternatively, siRNAs (small interfering RNA), short, single- or double-stranded ribonucleic acid molecules with a length of 20 to 25 base pairs can be used. They capture complementary single-stranded RNA molecules and thus inhibit the expression of the corresponding protein. Preferably, the carbon dioxide enrichment is further inhibited by carboxyzymes and pyrenoids. For this purpose, the expression of carbonic anhydrase (EC 4.2.1.1.) Required in carbonoxides for carbon dioxide enrichment is suppressed by shRNA, siRNA or other methods such as gene knockouts. Preferably, the ribulose-1,5-bisphosphate carboxylase / oxygenase (EC 4.1.1.39) and / or glycolic acid phosphate phosphatase (EC 3.1.3.18) are overexpressed. The overexpression can be carried out by introducing a plasmid with the respective gene into the organism or by optionally multiple incorporation of an overexpression cassette with the respective gene in the genome of the organism, wherein the gene is flanked by a strong promoter. RuBisCO is within the Calvin cycle for the Carbon dioxide / oxygen assimilation determining enzyme, while the glycolic acid phosphate phosphatase precedes the production of secreted glycolic acid ( FIG. 10 ). The expression of both enzymes therefore leads to an increased production of glycolic acid. More preferably, Type II RuBisCO is expressed in the PTM. Expression can be accomplished by introducing a plasmid or cassette into the genome. Type II RuBisCO, which is of bacterial origin, has a higher turnover number than RuBisCO Type I, so incorporation for higher productivity is beneficial. Preferably, the excretion of organic material in particular of glycolic acid is enhanced by the cell membrane. This is done by the overexpression or the increased activation of transporter proteins in the cell membrane, which are responsible for the transport of the respective organic material. The beneficial cyanobacteria do not require targeting of the transporters into compartmental membranes because prokaryotes have no compartments corresponding to the other PTMs, whereas eukaryotic PTMs are required.

The device according to the invention for the production of biogas in a combined fermenter comprises a first section, which is partially translucent, with phototrophic microorganisms which are located in a medium. The light transmission is ensured by the use of transparent materials such as glass, forms of acrylic glass (polymethyl methacrylate), polycarbonate, polyvinyl chloride, polystyrene, polyphenylene ether and polyethylene. The first section is preferably designed as a flat module comparable to a solar panel, since the depth of the first section is limited by the maximum illumination depth within the axis along the solar radiation. According to the invention, the PTM are immobilized such that more than 90% of the incident solar radiation is absorbed, with a thickness of not more than 10 mm is not exceeded. The modules are suitable for easy installation on open spaces or roofs and can be combined and expanded as required. After reaching the lifetime of the PTM, these can be replaced and fed to conventional biogas plants as yield-increasing admixture.

The apparatus further comprises a second portion that is opaque with methane formers that are in the medium that is exchanged with the first portion in the exchange mode, thereby reducing the oxygen content. A further component is a connection system between the first section and the second section, in which the exchange and the degassing of the medium takes place with the aid of filters, the filters being connected to gas supply and gas discharge lines. Another component is a biogas discharge from the second section for the discharge of the resulting biogas. Pumps and valves serve to distribute the liquid and gas streams according to the example explained with reference to the drawings embodiment. The further embodiment of the device depends on the advantageous methods described above. Preferably, both sections are connected to containers which contain nutrients such as trace elements or serve for the removal of by-products. The materials of the two sections aside from The transparent area in the first section are for example metals or plastics according to the claims.

In a preferred embodiment of the device according to the invention, the connection system comprises a first and second connection pipe for the possible establishment of a whole-reactor circulation in the exchange mode. Furthermore, the connection system preferably comprises a cross connection tube which connects the first connection tube and the second connection tube. As a result, a partial reactor circuit for the transitions between regeneration and production mode can be established. Further preferably, filters are provided as portions of the connecting pipes between the sections and the cross-connecting pipe. These filters are used for aeration and degassing in the exchange mode (first to fourth filter) and in the transitions from the exchange mode to the regeneration mode and from the regeneration mode to the production mode (first and second filters). Furthermore, the device preferably comprises a second cross-connection tube which connects the first section and the cross-connection tube, and a fifth filter as a section of the second cross-connection tube with an air duct with air filter preferably with a pore size of 0.2 microns or smaller for sterilization of the sucked air. The fifth filter is used for the ventilation and degassing with air in the transitions from the exchange mode to the regeneration mode and the regeneration mode to the production mode, wherein the first and second filters perform their respective oxygen degassing function. Preferably, the fermenter has an oxygen discharge, an oxygen supply, a substitute gas discharge and a replacement gas supply, each connected to a gas pump and the respective filter and a replacement gas storage and an oxygen storage, respectively connected to the replacement gas or oxygen lines. As a result, the gases can be temporarily stored after combined degassing and degassing operations. Furthermore, the biogas discharge from the second section is preferably transferred into a biogas filter and subsequently into a biomethane storage tank. Preferably, the biogas filter is connected to the replacement gas storage. As a result, the carbon dioxide diverted through the biogas filter can be made available to the replacement gas cycle again. Provision of superfluous carbon dioxide in the regeneration mode is also conceivable. It is in the result of a double circuit. A pH sensor in the first section preferably serves to determine how high the organic acid content is in the medium and when to initiate the exchange mode accordingly. Alternatively, solar sensors can be used to detect the activity of the PTM.

In a preferred embodiment of the device according to the invention, the first section is protected from excessive solar radiation. This serves to protect the PTM, whose photosystems can be damaged by excessive sunlight and / or which are endangered by the release of harmful reactive oxygen species. In particular, the translucent area of the first section can be darkened stepwise. For example, electrochromic materials may be used in the translucent region of the first section.

In a preferred embodiment of the device according to the invention, the phototrophic microorganisms are preferably immobilized on cellulose or a mobile carrier material, in particular in gas-permeable gel capsules and the methanogens preferably immobilized on activated carbon and / or a mobile carrier material, in particular in gas-permeable gel capsules. The immobilization serves to fix the PTM and the methanogens in the sections intended for them. Only the medium should be replaced. Immobilization methods such as (covalent) surface bonding, pore filling, cross-linking, membrane separation, and inclusion immobilization are possible. For example, the preferably biofilm-forming PTM can grow on a support surface such as cellulose, alginate, chitosan or agar. Movable supports are also conceivable, which are retained at the exit of the section by a filter and thereby contribute to immobilization in the respective section. Furthermore, so-called Immobilisierungstags come into consideration, i. Proteins that are expressed recombinantly on the surface of the microorganisms and ensure there binding to a carrier material. The methanogens can also be advantageously immobilized on activated carbon.

From the description of the method according to the invention and the device according to the invention, advantageous effects of the invention over the prior art and also the industrial applicability result.

The advantageous effects of the invention over the prior art include optimal, above all, energy-efficient transfer of the organic material from an aerobic section of the combined fermenter to an anaerobic section. In this case, an improved ventilation of the microorganisms is achieved without unnecessary gas consumption. In addition, in a preferred variant, it is possible to assimilate carbon dioxide (and nitrogen) from the air and thus initiate a climate- or CO2-neutral process, which results in the release of carbon dioxide during the biomethane combustion. As a result, the method according to the invention is more effective in the apparatus provided, especially in comparison with the production of biogas from plants, which concerns not only the lower arable land use and the high costs for the production of the biomass: Biogas yield m ³ / t biomass (organ. Methane content in% Corn 198 54 grass 158 52.9 Euk. PTM 400 (0.24 ml / mg glyks.- 5/3 × 10 ³ ) 37.5 Conv. Biogas figures from Schwab M. 2007

• Figur 1 zeigt eine zweidimensionale Ansicht einer erfindungsgemäßen Vorrichtung zur Durchführung des Verfahrens, wobei gestrichelte Stellen einen Ebenenübergang darstellen.
• Figuren 2-6 zeigen Ansichten des in Figur 1 dargestellten Fermenters in mehreren Modi.
• Figur 7 zeigt den Aufbau eines vorzugsweise als Filter einzusetzenden Hohlfaserkontaktors.
• Figur 8 zeigt schematisch den Ablauf des Calvinzyklus in phototrophen Mikroorganismen unter kohlenstoffdioxidreichen Bedingungen (linke Seite) und unter sauerstoffreichen Bedingungen (rechte Seite).
• Figur 9 zeigt die durch RuBisCO katalysierten Reaktionen mit den beteiligten Molekülen in Strukturformeln.
• Figur 10 zeigt die Oxygenasereaktion der RuBisCO und die weitere Verstoffwechslung der dadurch entstandenen Phospho-Glycolsäure mit den beteiligten Molekülen in Strukturformeln und den Enzymen.
• Figur 11 zeigt ein Diagramm zur Glycolsäureproduktion in µmol pro mg Chlorophyll a durch Gloeothece 6909 bei unterschiedlichem Sauerstoff-/Kohlenstoffdioxidverhältnis und unterschiedlichen Bestrahlungsstärken.

Description of the drawings

• FIG. 1 shows a two-dimensional view of a device according to the invention for carrying out the method, wherein dashed lines represent a plane transition.
• Figures 2-6 show views of in FIG. 1 shown fermenter in several modes.
• FIG. 7 shows the structure of a preferably used as a filter hollow fiber contactor.
• FIG. 8 shows schematically the course of the Calvinzyklus in phototrophic microorganisms under carbon dioxide-rich conditions (left side) and under oxygen-rich conditions (right side).
• FIG. 9 shows the reactions catalyzed by RuBisCO with the molecules involved in structural formulas.
• FIG. 10 shows the oxygenase reaction of RuBisCO and the further metabolism of the resulting phospho-glycolic acid with the molecules involved in structural formulas and the enzymes.
• FIG. 11 shows a graph of glycolic acid production in μmol per mg of chlorophyll a by Gloeothece 6909 at different oxygen / carbon dioxide ratio and different irradiance.

Description of an embodiment

In the in FIG. 2 The phototrophic microorganisms (1) Gloeothece 6909, which were previously attracted and immobilized on a surface, produce glycolic acid under oxic conditions and sunlight, which they secrete into the medium (3) ( Figures 9 and 11 ). In this mode all valves of the first section (2) and the second section (4) to the connection system (6) are closed. In direct sunlight in midsummer, the duration of the production mode is one hour. A controlling clock accordingly ends the production mode.

In the in FIG. 3 In the illustrated exchange mode, the valves to the first connection pipe (8) and to the second connection pipe (9) are opened while the valves to the first cross connection pipe (10) and to the second cross connection pipe (15) are closed. The first pump (27) and the second pump (28), which are configured as peristaltic pumps, then pump the medium (3) from the first section (2) into the second section (4). In this case, the medium passes through the first filter (11), which in this embodiment, like the other filters, is also designed as a hollow-fiber contactor ( FIG. 7 ). A gas pump (30) in the form of a vacuum pump in the permeate space (31) between the partitions (32) and the hollow fibers (33), which are flowed through by the medium (3) from the input space (34) to the output space (35), a vacuum ago. The oxygen molecules leave the liquid and penetrate through the hollow fibers into the permeate space (31). From there they are pumped through the gas pump (30) and transported through a pipe to the oxygen storage (24) and from there to the second filter (12). Meanwhile, the degassed medium leaves the first filter (11) and passes through the first connecting pipe (8) to the third filter (13), where a gas pump (30) generates an overpressure in the permeate space of carbon dioxide. As a result, the carbon dioxide molecules from the replacement gas reservoir (23) pass through the hollow fibers into the medium (3). The medium (3) flows in the sequence in the second section (4). There consume methanogen (5), which were previously selected for Glycolsäureverwertung and immobilized, the glycolic acid and convert it into a gas mixture consisting of Biomethane and carbon dioxide in a ratio of 3 to 5 microns bubbling up in bubbles. A biogas outlet (7) collects the gas stream and passes it through a biogas filter (25), a hollow fiber contactor for the separation of gases, in which the carbon dioxide is separated and directed into the replacement gas reservoir (23). By contrast, the purified biomethane is stored in the biomethane storage tank (26). The medium (3) leaves the second section (4) and is degassed in the fourth filter (14) by carbon dioxide, which in turn is provided for gassing by the third filter (13) or storage in the replacement gas reservoir (23). Through the second filter (12) the medium (3) is again gassed with oxygen, which comes from the degassing of the first filter (11). The medium (3), which is now reoxygenated, returns to the first section (2). Once the medium (3) has been exchanged between sections, a new production mode begins. After at least two passes of the production and exchange modes, the transition to the regeneration mode begins.

In the transition to the regeneration mode, the valves of the second section (4), a part of the first connection pipe (8), the second connection pipe (9) and a part of the first cross connection pipe (10) are corresponding to FIG. 4 closed. The first pump (27) circulates the medium (3) through the first part of the first connection pipe (8), the upper part of the first cross connection pipe (10) and the second cross connection pipe (15). In this case, the medium (3) first passes through the first filter (11), in which it is degassed by oxygen, which is temporarily stored in the oxygen reservoir (24). Thereafter, the medium (3) flows through the fifth filter (16) and is there with ambient air, which is sucked through an air line (17) and through an air filter (18) fumigated. The medium finally returns to the first section (2).

In the regeneration mode, the valves of the connection system sections (6) are as in FIG. 5 shown closed. When exposed to sunlight, the PTM releases carbon ( FIG. 8 ) and nitrogen from the air dissolved in the medium (3) assimilated. The duration of the regeneration mode depends on the duration of a run of the production mode.

In the transition to the production mode, the valves of the second section (4), the first connecting pipe (8), a part of the second connecting pipe (9) and a part of the first cross-connecting pipe (10) according to FIG. 6 closed. The second pump (28) circulates the medium (3) through the first part of the second connection pipe (9), the lower part of the first cross connection pipe (10) and the second cross connection pipe (15). In this case, the medium (3) initially passes the fifth filter (16), in which it is degassed by the remaining air, which is discharged through the air line (17) and through the air filter (18) into the environment. Thereafter, the medium (3) flows through the second filter (12) and is there gassed with the previously stored oxygen from the oxygen storage (24). It finally returns to the first section (2). The valves of the first section (2) are closed. The production mode starts with sunlight irradiation, which is registered by a solar detector.

• Barber J. 2009 - Photosynthetic energy conversion: natural and artificial, Chemical Society Reviews 2009 (38), S. 185-196
• Bauwe H. 2011 - Photorespiration: The Bridge to C4 Photosynthesis. In: Agepati S. Raghavendra (Hrsg.) und Rowan F. Sage (Hrsg.): C4 Photosynthesis and Related CO2 Concentrated Mechanisms (Advances in Photosynthesis and Respiration), Springer Netherlands 2011, S. 81-108
• Bericht des FHI 2011 - Algen - nachhaltige Rohstoffquelle für Wertstoffe und Energie, Fraunhoferinstitut für Grenzflächen- und Bioverfahrenstechnik 2011, S. 2
• Bernacchi S. et al. 2014 - Process efficiency simulation for key process parameters in biological methanogenesis, AIMS Bioeng. 2014 (1), S. 53-71
• Blankenship R.E. et al. 2011 - Comparing Photosynthetic and Photovoltaic Efficiencies and Recognizing the Potential for Improvement, Science 2011 (332), S. 805-809
• Carrieri D. et al. 2015 - Enhancing photo-catalytic production of organic acids in the cyanobacterium Synechocystis sp. PCC 6803 ΔglgC, a strain incapable of glycogen storage, Microb. Biotechnol. 2015 (8), S. 275-280
• Dismukes G.C. et al. 2008 - Aquatic Phototrophs: efficient alternatives to land-based crops for fuels, Current Opinion in Biotechnology 2008 (19), S. 235-240
• Doravari S. et al. 1980 - Effect of butyl 2-hydroxy-3-butynoate on sunflower leaf photosynthesis and photorespiration, Plant Physiol. 1980 (66), S. 628-631
• Edenborn H.M. et al. 1985 - Glycolate metabolism by Pseudomonas sp., strain S227, isolated from a coastal marine sediment, Marine Biology (88), S. 199-205
• Egli C. et al. 1989 - Monochloro- and dichloroacetic acids as carbon and energy sources for a stable, methanogenic mixed culture, Arch. Microbiol. 1989 (152), S. 218-223
• Fachverband Biogas Prognose - Branchenzahlenprognose für die Jahre 2014 und 2015, Fachverband Biogas e.V., Juni 2014, S. 2
• Friedrich M. et al. 1991 - Fermentative degradation of glycolic acid by defined syntrophic cocultures, Arch. of Microbiol. 1991 (156), S. 398-404
• Friedrich M. et al. 1996 - Phylogenetic Positions of Desulfofustis glycolicus gen. nov., sp. nov., and Synthrobotulus glycolicus gen. nov., sp. nov., Two New Strict Anaerobes Growing with Glycolic Acid, Int. J. of Sys. Bact., 1996, S. 1065-1069
• Günther A. et al. 2012 - Methane production from glycolate excreting algae as a new concept in the production of biofuels, Biores. Tech. 2012 (121), S. 454-457
• Kurz W.G.W, et al. 1973 - Metabolism of glycolic acid by Azotobacter chroococcum PRL H62, Can. J. of Microbiol. 1973 (19), S. 321-324
• Latifi A. et al. 2009 - Oxidative stress in cyanobacteria, FEMS Microbiol. Rev. 2009 (33), S. 258-278
• Linder H. 1998 - Biologie, Schroedel, 21. Aufl. 1998, S. 43
• Lorimer G.H. 1981 - The carboxylation and oxygenation of ribulose 1,5-bisphosphate; The primary events in photosynthesis and photorespiration. Ann. Rev. Plant Physiol. 1981 (32), S. 349-383
• MacColl R. 1998 - Cyanobacterial phycobilisomes, J. Struct. Biol. 1998 (15), S. 311-334 Masukawa H. et al. 2012 - Genetic Engineering of Cyanobacteria to Enhance Biohydrogen Production from Sunlight and Water, AMBIO 2012 (41), S. 169-173
• Miller A.G. et al. 1989 - Glycolaldehyde Inhibits CO2 Fixation in the Cyanobacterium Synechococcus UTEX 625 without Inhibiting the Accumulation of Inorganic Carbon or the Associated Quenching of Chlorophyll a Fluorescence, Plant Phys. 1989 (91), S. 1044-1049
• Moroney J. V. et al. 1986 - Glycolate metabolism and excretion by Chlamydomonas reinhardtii, Plant Physiol. 1986 (82), S. 821-826
• Moroney J.V. et al. 2001 - Carbonic anhydrases in plants and algae, Plant, Cell & Env. 2001 (24), S. 141-153
• Nabors M.W. et al. 2007 - Botanik, Pearson Studium, 1. Aufl. 2007, S. 221-222
• Renström E. et al. 1989 - Glycolate metabolism in cyanobacteria. I. Glycolate excretion and phosphoglycolate phosphatase activity, Phys. Plant. 1989 (43), S. 137-143
• Sari, S. 2010 - Untersuchung der Dehydrogenierung von NADH/NADPH in isolierten und gereinigten Membranen von drei verschiedenen Cyanobakterienspezies, die in zwei verschiedenen Bedingungen gezüchtet wurden, Diplomarbeit, Universität Wien 2010, S. 8
• Schwab M. 2007 - Biogaserträge aus Energiepflanzen - Eine kritische Bewertung des Datenpotentials, Kuratorium für Technik und Bauwesen in der Landwirtschaft e. V. 2007, S. 4
• Stein J. 1973 - Handbook of Phycological methods. Culture methods and growth measurements. Cambr. Univ. Press. 1973, S. 448ff .
• Stenberg K. 1997 - Three-dimensional structures of glycolate oxidase with bound active-site inhibitors, Prot. Sc. 1997 (6), S. 1009-1015
• Zelitch I. 1966 - Increased Rate of Net Photosynthetic Carbon Dioxide Uptake Caused by the Inhibition of Glycolate Oxidase, Plant Physiol. 1966 (41), S. 1623-1631

The following non-patent literature was cited:

• Barber J. 2009 - Photosynthetic energy conversion: natural and artificial, Chemical Society Reviews 2009 (38), pp. 185-196
• Bauwe H. 2011 - Photorespiration: The Bridge to C4 Photosynthesis. In: Agepati S. Raghavendra (ed.) And Rowan F. Sage (ed.): C4 Photosynthesis and Related CO2 Concentrated Mechanisms (Advances in Photosynthesis and Respiration), Springer Netherlands 2011, pp. 81-108
• Report of the FHI 2011 - Algae - sustainable raw material source for recyclables and energy, Fraunhofer Institute for Interfacial Engineering and Biotechnology 2011, p. 2
• Bernacchi S. et al. 2014 - Process efficiency simulation for key process parameters in biological methanogenesis, AIMS Bioeng. 2014 (1), pp. 53-71
• Blankenship RE et al. 2011 - Comparing Photosynthetic and Photovoltaic Efficiencies and Recognizing the Potential for Improvement, Science 2011 (332), pp. 805-809
• Carrieri D. et al. 2015 - Enhancing photo-catalytic production of organic acids in the cyanobacterium Synechocystis sp. PCC 6803 ΔglgC, a strain incapable of glycogen storage, Microb. Biotechnol. 2015 (8), pp. 275-280
• Dismukes GC et al. 2008 - Aquatic Phototrophs: efficient alternative to land-based crops for fuels, Current Opinion in Biotechnology 2008 (19), pp. 235-240
• Doravari S. et al. 1980 - Effect of butyl 2-hydroxy-3-butynoate on sunflower leaf photosynthesis and photorespiration, Plant Physiol. 1980 (66), pp. 628-631
• Edenborn HM et al. 1985 - Glycolate metabolism by Pseudomonas sp., Strain S227, isolated from a coastal marine sediment, Marine Biology (88), pp. 199-205
• Egli C. et al. 1989 - Monochloro- and dichloroacetic acids as carbon and energy sources for a stable, methanogenic mixed culture, Arch. Microbiol. 1989 (152), pp. 218-223
• Fachverband Biogas Prognosis - Industry Forecast for the years 2014 and 2015, Fachverband Biogas eV, June 2014, p. 2
• Friedrich M. et al. 1991 - Fermentative degradation of glycolic acid by defined syntrophic cocultures, Arch. Of Microbiol. 1991 (156), pp. 398-404
• Friedrich M. et al. 1996 - Phylogenetic Positions of Desulfofustis glycolicus gen. Nov., Sp. nov., and Synthrobotulus glycolicus gen. nov., sp. nov., Two New Strict Anaerobic Growing with Glycolic Acid, Int. J. of Sys. Bact., 1996, pp. 1065-1069
• Günther A. et al. 2012 - Methane production from glycolate excreting algae as a new concept in the production of biofuels, Biores. Tech. 2012 (121), pp. 454-457
• WGW, et al. 1973 - Metabolism of glycolic acid by Azotobacter chroococcum PRL H62, Can. J. of Microbiol. 1973 (19), p. 321-324
• Latifi A. et al. 2009 - Oxidative stress in cyanobacteria, FEMS microbiol. Rev. 2009 (33), pp. 258-278
• Linder H. 1998 - Biology, Schroedel, 21st ed. 1998, p. 43
• Lorimer GH 1981 - The carboxylation and oxygenation of ribulose 1,5-bisphosphates; The primary events in photosynthesis and photorespiration. Ann. Rev. Plant Physiol. 1981 (32), pp. 349-383
• MacColl R. 1998 - Cyanobacterial phycobilisome, J. Struct. Biol. 1998 (15), pp. 311-334 Masukawa H. et al. 2012 - Genetic Engineering of Cyanobacteria to Enhance Biohydrogen Production from Sunlight and Water, AMBIO 2012 (41), pp. 169-173
• Miller AG et al. 1989 - Glycolaldehyde Inhibits CO2 Fixation in the Cyanobacterium Synechococcus UTEX 625 without Inhibiting the Accumulation of Inorganic Carbon or the Associated Quenching of Chlorophyll a Fluorescence, Plant Phys. 1989 (91), pp. 1044-1049
• Moroney JV et al. 1986 - Glycolate metabolism and excretion by Chlamydomonas reinhardtii, Plant Physiol. 1986 (82), pp. 821-826
• Moroney JV et al. 2001 - Carbonic anhydrases in plants and algae, Plant, Cell & Env. 2001 (24), pp. 141-153
• Nabors MW et al. 2007 - Botany, Pearson Studium, 1st edition 2007, pp. 221-222
• Renström E. et al. 1989 - Glycolate metabolism in cyanobacteria. I. Glycolate excretion and phosphoglycolate phosphatase activity, Phys. Plant. 1989 (43), pp. 137-143
• Sari, S. 2010 - Investigation of Dehydrogenation of NADH / NADPH in Isolated and Purified Membranes of Three Different Cyanobacteria Species Grown in Two Different Conditions, Diploma Thesis, University of Vienna 2010, p. 8
• Schwab M. 2007 - Biogas yields from energy crops - A critical evaluation of the data potential, Board of Trustees for technology and construction in agriculture e. V. 2007, p. 4
• Stein J. 1973 - Handbook of Phycological methods. Culture methods and growth measurements. Cambr. Univ. Press. 1973, p. 448ff ,
• Stenberg K. 1997 - Three-dimensional structures of glycolate oxidase with bound active-site inhibitors, Prot. Sc. 1997 (6), pp. 1009-1015
• Zelitch I. 1966 - Increased Rate of Net Photosynthetic Carbon Dioxide Uptake Caused by the Inhibition of Glycolate Oxidase, Plant Physiol. 1966 (41), pp. 1623-1631

Claims (15)

1. A method for the production of biogas in a combined fermenter, in which phototrophic microorganisms (1) in a first section (2) produce organic material, in particular glycolic acid from carbon dioxide and oxygen, and secrete it into a medium (3) (production mode) that is fed into a second section (4) in which methanogens (5) produce biomethane and carbon dioxide under anoxic conditions, characterized in that the medium (3) is degassed by oxygen during the transition from the first section (2) to the second section (4) and is backfilled with oxygen during a return (exchange mode).
2. A method according to claim 1, characterized in that, while the contact to the second section (4) is interrupted,

   - the medium (3) is degassed by oxygen and is gassed with air from the environment during a return;

   - the air is then used by the phototrophic microorganisms (1) for carbon assimilation (regeneration mode);

   - the medium (3) is then degassed by air and gassed with oxygen-during a return flow.
3. A method according to claim 1 or 2, characterized in that the ratio of carbon dioxide to oxygen in the medium (3) in the production mode located in the first section (2) is low, preferably 1: 800 to 1: 3000.
4. A method according to one of the preceding claims, characterized in that in the exchange mode the medium (3) is gassed with a substitute gas after the oxygen degassing during the transition from the first section (2) to the second section (4), in particular with carbon dioxide or nitrogen, and that it is degassed by the substitute gas before the oxygen gassing.
5. A method according to one of the preceding claims, characterized in that the carbon dioxide is separated from the biogas produced in the second section (4) and is used for carbon dioxide gassing according to claim 4.
6. A method according to one of the preceding claims, characterized in that, in particular, hollow fiber contactors are used for the gassing and degassing, the pore size being less than 0.1 µm, preferably less than 0.04 µm.
7. A method according to one of the preceding claims, characterized in that cyanobacteria are used as phototrophic microorganisms (1), preferably biofilm-forming and preferably slightly more preferably metabolizing less than 10 % of the produced organic material, in particular Gloeothece 6909, Plectonema boryanum, Anabaena sp. and Nostoc sp.
8. A method according to one of the preceding claims, wherein the methanogens (5) in the second section (4) are a mixture of acetotrophic and hydrogenotrophic archaea, wherein the acetotrophic archaea, in particular methanosarcina or synthrophobotulus, segregate the organic material from the first section (2) in carbon dioxide and hydrogen which is used by hydrogenotrophic archaea, in particular Methanocella paludicola, Methanocella arvoryzae or Methanopyrus kandleri, for biomethane production and / or mixed cultures obtained by selection from sediments of lakes and oceans, bovine pans, intestines of termites and other animals, rice fields, marshes or biogas plants.
9. A method according to one of the preceding claims, characterized in that inhibitors of the intracellular degradation of the organic material and / or of the intracellular carbon dioxide storage are present in the first section (2).
10. A method according to one of the preceding claims, characterized in that in the phototrophic microorganisms (1)

    - the expression and / or the activity of the glycolic acid dehydrogenase and / or glycolic acid oxidase is suppressed;

    - the carbon dioxide accumulation by carboxysomes and pyrenoids is inhibited;

    - the ribulose 1,5-bisphosphate carboxylase / oxygenase and / or glycolic acid phosphate phosphatase are overexpressed;

    - the ribulose 1,5-bisphosphate carboxylase / oxygenase type II is expressed;

    - the excretion of organic material, especially of glycolic acid, is enhanced by the cell membrane.
11. A device for producing biogas in a combined fermenter comprising the following components:

    - a first section (2), which is partially transparent, with phototrophic microorganisms (1) which are located in a medium (3);

    - a second section (4) which is opaque, with methanogens (5) located in the medium (3) which is exchanged in exchange mode with the first section (2), the oxygen content being reduced;

    - a connecting system (6) between the first section (2) and the second section (4);

    - filters in the connecting system (6) for the gassing and degassing of the medium (3) which are connected to gas supply and gas outlets,

    - a biogas effluent (7) from the second section (4);

    - pumps and valves for the distribution of liquid and gas streams.
12. A device according to claim 11, characterized in that

    - the connecting system (6) comprises a first connecting pipe (8) and a second connecting pipe (9);

    - the connecting system (6) comprises a first cross-connect tube (10) interconnecting the first connecting pipe (8) and the second connecting pipe (9);

    - a first filter (11) is a part of the first connecting pipe (8) between the first section (2) and the first cross-connecting pipe (10);

    - a second filter (12) is a part of the second connecting pipe (9) between the first section (2) and the first cross-connecting pipe (10);

    - a third filter (13) is a part of the first connecting pipe (8) between the second section (4) and the first cross-connecting pipe (10);

    - a fourth filter (14) is a part of the second connecting pipe (9) between the second section (4) and the first cross-connecting pipe (10);

    - a second cross-connect tube (15) connecting said first section (2) and said first cross-connect tube (10);

    - a fifth filter (16) is a part of the second cross-connect tube (15) and is connected to an air line (17) with air filter (18), preferably with a pore size of 0.2 µm or less;

    - an oxygen effluent (19), an oxygen supply line (20), a substitute gas supply line (21) and a substitute gas discharge line (22);

    - a spare gas storage (23) and an oxygen storage (24) are present;

    - a biogas filter (25) is provided as a part of the biogas effluent (7) with a subsequent biomethane storage tank (26);

    - the spare gas storage (23) is connected to the biogas filter (25);

    - a first pump (27) as a part of the first cross-connect tube (8) between the first section (2) and the first filter (11) and a second pump (28) as a part of the second connecting pipe (9) between the first cross-connect tube (10) and the second Filter (12) is present.
13. A device according to one of the preceding claims, characterized in that the first section (2) is protected from excessive solar radiation, in particular the light-transmissivie region (29) of the first section (2) can be darkened step by step.
14. A device according to one of the preceding claims, characterized in that the phototrophic microorganisms (1) are preferably immobilized on cellulose or a mobile carrier material, in particular gas-permeable gel capsules and the methane generators (5) preferably on activated carbon or a mobile carrier material, in particular gas-permeable gel capsules.
15. A device according to one of the preceding claims, characterized in that the filters are hollow fiber contactors, in particular with a gas pump (30), a permeate chamber (31), partitions (32), hollow fibers (33), an input space (34) and an output space (35).

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